Sheet-forming and post-forming trim method and apparatus



June 18, 1968 R. E. O'BRIEN ETAL. 3,388,625

SHEET-FORMING AND POST-FORMING TRIM METHOD AND APPARATUS 5 Sheets-Sheet1 Original Filed July 15, 1965 s vw Obb ATTORNEYS June 18, 1968 R. E.OBRIEN ETAL 3,388,625

SHEET-FORMING AND POST-FORMING TRIM METHOD AND APPARATUS 5 Sheets-Sheetl2 Original Filed July 15, 1965 ffff L ATTORNEYS June 18, 1968 R. E.o'BRu-:N ETAL 3,388,625

SHEET-FORMING AND POST-FORMING TRIM METHOD AND APPARATUS 5 Sheets-Sheet5 Original Filed July 15, 1965 ATTORNEYS June 18, 1968 R, E, oBRlEN ETAL35388,625

SHEET'FORMING AND POST-FORMING TRIM METHOD AND APPARATUS 5 Sheets-Sheet4 Original Filed July l5, 1965 ATTORNEYS June 18, 1968 R. E. O'BRIENETAL 3,388,625

- SHEET-FORMING AND POST-FORMING TRIM METHOD AND APPARATUS 5Sheets-Sheetl 5 Original Filed July l5, 1965 ATTORNEYS b n om mw@ I 4 rw @wm WZ bw B Unite States Patent O' 3,388,625 SHEET-FGRMING ANDPGST-FORMNG TREM METHQD AND APPARATUS Robert E. Brien, Dietrich K. Roth,and Edward Markowski, Grand Rapids, Mich., assignors to lirklaofManufacturing Corporation, Grand Rapids, Mich., a corporation ofMichigan Uriginai application July 15, 1965, Ser. No. 472,135, nowPatent No. 3,329,995, dated July 11, 1967. Divided and this applicationMay 4, 1967, Ser. No. 651,334

3 Claims. (Cl. 823-233) ABSTRACT F THE DSCLGSURE A trim process forthree dimensional articles is a web in repeat spaced patterns of aplurality of articles, hav ing web advancing means causing repeat normalstroke advancement and a periodic different stroke advancement.

This application is a divisional application of the parent applicationentitled Sheet-Forming and Post-Forming Trim Method and Apparatus, filedJuly 15, 1965, Ser. No. 472,135, by Robert E. OBrien, Edward C.Markowski, and Dietrich K. Roth.

This invention relates to apparatus for forming, advancing and severingthree dimensional articles from a generally continuous web ofplastically deformable material, and especially relates to web advancingand control means for and between forming and trim presses.

In apparatus for pressure forming three dimensional objects from agenerally continuous web on a mass production basis, particularly athermoplastic web, the articles are often formed into the web byphysical and/or pneumatic pressure differential techniques in areci-procating forming press, then subsequently severed from the web ina separate trim press. When forming the articles in the forming press,maximum efficiency is achieved by employing dies having a pattern of aplurality of like adjacent die faces to form a plurality of likearticles with each press stroke. Sometimes the patterns, each composedof a plurality of articles, are spaced from each other in the web `by anintermediate web portion. This spacing of patterns occurs in example, inwebs that travel through a preheat oven prior to entering the formingpress. This is because it has been found advisable to condition theportion of the web that is between the forming dies and the oven exit toprevent the web from distorting longitudinally through this portion.This can be done by blowing cold air on this section or by gripping itas explained more fully in copending patent application entitled SheetPreheating and Forming Method and Apparatus, Ser. No. 474,034, liledJuly 22, 1965 and assigned to the assignee herein.

This spacing of the patterns of pluralities of articles creates aproblem with web advancement in the trim press which must operate oneach article. The advancing means normally advances the web uniformamounts equal to the width of each article. The last article in apattern and the rst article in the next pattern, however, are spaced agreater amount because of the web section between the patterns, asmentioned above.

Another difficulty occurring with web advancement from the forming pressto the trim press is due to the fact that the web in the forming pressis intermittently advanced each time an amount equal to the width of thepattern of several articles plus the space between the patterns, whilethe trim press is advanced only one article at a time. Yet, the webbetween the presses cannot get too taut or it will break, and cannot gettoo loose or its slack will drag on the floor, get tangled in theequipment, etc.

It is an object of this invention to provide web ad vancing and controlapparatus for forming and trimming equipment of plastically deformableweb material, achieving controlled correlated relationship between thearticle forming press and the article severing trim press.

Another object of this invention is to provide variable spaced webadvancing means and correlated control means between the forming pressand the trim press of pressure forming equipment for plastic webmaterial, preventing excess web slackness and excess web tightness, andalways automatically maintaining a controlled zone of tightness in theweb between the presses, even though the presses tend to advance the webat different rates.

Another object of this invention is to provide a web advancing means forarti-cle trim press units, causing controlled feed of articles in repeatspaced patterns of pluralities of articles, to do so one article at atime, even when the spaces between the patterns are encountered. Theadvancing means in the trim press normally repeatedly shifts the web awidth equal to one article, and uniquely automatically shifts the web anextra amount, periodically, to cover the space between the patterns ofarticles.

Another object of this invention is to provide an improved plasticarticle forming, advancing, and trimming apparatus for forming andsevering three dimensional plastic articles from a generally continuousthermoplastic web.

These and several other objects of this invention will become apparentupon studying the following specification in conjunction with thedrawings in which:

FIG. l is a perspective View of the complete forming, advancing and trimequipment for forming and severing three dimensional articles from agenerally continuous plastically deformable web;

FIG. 2 is a side elevational view of the trim press forming part of theapparatus in FIG. l;

FIG. 3 is an enlarged fragmentary perspective view of a portion of thetrim press in FIG. l, particularly showing a portion of the webadvancing means for the trim press;

FIG. 4 is a side elevational view of the web advancing lever means inFlG. 3;

FIG. 5 is a rear elevational view of the apparatus in FIG. 4;

FIG. 6 is a top plan View of the apparatus in FIG. 4;

FIG. 7 is a sectional view of the apparatus in FIG. 6, taken on planeVII-VII;

FIG. 8 is a side elevational, enlarged view of the trim press advancingapparatus;

FIG. 9 is a perspective view of the variable speed power motor drivecontrol means for the web advancing apparatus; and

FIG. l() is a cutaway perspective view of the variable speed drive meansin FIG. 9.

Referring now specifically to the drawings, particularly FIG. l, thecomplete apparatus 10 there shown includes a forming press assembly 12,a trim press assembly 14, and a web sensor assembly 16 between thepresses.

The forming press assembly 12 includes a pair of spaced upright pillars20 and 22 with a cross beam 24 between the top ends thereof, and asupport base 26 beneath the bottom ends thereof. The head 28 of thepress has suspended therefrom a vertically reciprocable upper ram 30with an upper die 32 mounted to the bottom thereof. This is operated bya toggle linkage 34 which may be actuated as by pressure cylinder means(not shown).

The lower die mounted to the bed 36 of the press may be nxed andstationary, or alternatively, vertically reciprocable by a second togglelinkage (not shown in detail) operated by another liuid cylinder 3S. Theapparatus for this structure includes web advancing means such as thepair of chain elements on opposite sides of the press, extending fromand advanceable through the preheat oven 42 to the outlet of the pressadjacent guide surface 44. Further details of the press may be seen ingreater detail in copending application entitled Universal FormingPress, Ser. No. 474,132, filed July 22, 1965, now Patent No. 3,340,574,to the assignee herein.

The dies can use physical pressure and/or pneumatic pressuredifferential to form the articles into the thermoplastic web. Thethermoplastic web is fed to the forming press from a roll of generallycontinuous length, and rotatably supported on suitable stand means 52 toallow the web to be continuously pulled off, fed into and through thepreheat oven 42 of selected length, and then between the dies of thereciprocable press, as advanced by moving chains 40. These chains can bedriven by a suitable motor. The preheat oven can be formed according tothe teachings in copending application entitled sheet Preheating andForming Method and Apparatus, Ser. No. 474,- 034, filed July 22, 1965.

The plastic web 50a entering into forming press has formed into it aplurality of three dimenstonal articles 50h. Those are integrallypressed into its surface by the forming dies in selected spacedpatterns, each pattern containing a plurality of like articles, asillustrated in FIG. 1. The web has a space 50c of webbing portionbetween the pattern. This space may be because of a conditioningtreatment such as cooling air being blown onto this web portion betweenthe preheat oven 42 and the forming press dies to prevent distortion ofthe last articles in the pattern, as explained more fully in copendingapplication entitled Sheet Prelieating and Forming Method and Apparatus,Ser. No. 474,035, filed July 22, 1965, and assigned to the assigneeherein.

The web, with the articles formed into it but still intact, is conductedthrough a space between the otulet side of the forming press and thearcuate guide 62 leading into the top of the trim press assembly 14.Positioned in this space is the sensing assembly 16 of the web control,including an upper electrical switch web sensor unit 64 having a sensorfinger 66 extending out over the web, and a lower electrical switchsensor unit 68 having a sensor finger 70 extending out below the web.Both of these sensor units are mounted on a suitable support stand 72with a base 74. Electrical leads 78 and 80 extend respectively fromsensors 64 and 68. These extend to the control unit shown in FIG. 9, andspecifically the solenoid valve assembly 84, as discussed more fullyhereinatfer.

The guide assembly 62 has a generally arcuate, up and over supportsurface. It may be formed of a metal sheet mounted on a suitable supportstand 92, or the equivalent such as conveyor rollers or the like. On thedischarge, downwardly directed end of this guide is a pair of holdingrollers 94 and 96 mounted to the support in positions to press the edgesof the web 50c into downwardly directed relationship on its verticalpath into the trim press.

This trim press, shown more specifically in FIG. 2, includes a fixed dieplate 101 on support 100, and having an article passage opening 102therein, as well as a sharp peripheral edge around the opening. Thisplate is mounted fixedly to the framework 104 of the press, to becooperative with the trim die 106 attached lto the reciprocable ram 108.This ram is mounted to reciprocate horizontally, by suspension onbearing sleeves 110 and 112 slidable on fixed guide rods 114 and 116.The ram 108 is reciprocated horizontally toward and away from die plate100 by a crank pivotally attached at 122 to the rear end of the ram, andmounted on a conventional offset throw bearing of the crank shaft 130.Its offset axis rotates about the shaft axis as is usual and as isillustrated by the axes shown at 121 and 123 in' FIG. 6. The crank shaftis driven by a large fly wheel and pulley 132 which is rotated by Vbelts 134. These belts are driven by a variable speed electrical driveassembly 136 having a pulley 138 on its output shaft 137.

Mounted on the opposite end of crank shaft from fly wheel 132 is webadvancing means for the trim press, including a rotary cam 142 whichmakes one rotary revolution per each reciprocable revolution of the trimpress. Abutting the periphery of this rotary cam is a cam follower wheel144 rotatably mounted on the side of a vertically extending, arcuatelyrocking lever 146 that has two different pivot mounts. Morespecifically, the lower end of this lever is mounted to the pivotaljournal 148 at lower pivot mount 150. Closer to the cam and camfollower, i.e. between this pivot mount 150 and cam follower 144- is asecond upper pivot mount 152 intermediate the ends of the lever. Thelever has upper and lower parts overlapping at pivot 152. The lever 146,when appropriately treated, can pivot about either of those pivot mountsto have a different length stroke on link 154. Normally, pivotal actionof the lever with rotation of cam 142, occurs about lowermost pivot 150.The lever does not buckle at pivot 152, under its regular oscillation,since, even though there is some bending force applied by cam 142 thattends to cause bending about pivot 152, the backward force applied bylink 154 at the upper end of the lever tends to counteract this andmaintain the lever straight. The lever is made so that it can onlybuckle in one direction (clockwise as viewed in FIG. 2). This normalshifting of lever 146 causes its lever upper end to shift apredetermined distance in a slight arc, generally horizontally, tothereby shift link 154 a predetermined amount horizontally.

One end of link 154 is pivotally connected to the upper end of lever146, and the opposite end is pivotally connected to the downwardlydepending rocking arm 158. A shaft 162, suspended in journal bearings160, has a keyed connection to arm 158, and also is keyed to anothercantilever type arm 164. To the outer end of arm 164 is suspendedpushing means, specifically fingers 166. These pushing fingers, seenmore specifically in FIG. 8, have a bent lower end to catch behindpreformed articles 50h on web 50d, to push them downwardly as the armreciprocates. These fingers straddle trim die 106 and die orifice 102 inplate 100 so as to not interfere with the die cutting operation. Thelingers are pivotally mounted on their upper end to shift with the dieand hold the article and web portion down until the web is gripped bypivotal holding elements 169 which also swing with die movement. Thus,as cam 142 (FIG. 2) rotates, lever 146 rocks back and forth on pivot 150to shift link 154 back and forth, thereby rocking the depending arm 158and tilting the cantilever arm 164 between its solid line position andits phantom line position illustrated in FIG. 8. This shifts theadvancing pushing fingers 166 up and down between their solid lineposition and their phantom line position in FIG. 8, to thereby push onearticle down, and then back up while moving out and around the nextarticle to catch in behind this next article. The web and articles are,therefore, pushed down the vertical guide to place each article one at atime in front of die 106 so that, as the die .reciprocates, the articleis pushed into the die plate opening 102 and severed from the web. Thearticles are then collected on a suitable platform means 184 (FIG. 1) inhorizontally stacked fashion or in suitable containers.

Because a definite space 50c exists between each pattern. of a pluralityof formed articles, the trim press advancing -rneans must account forthis. The advancing means normally advances the web with its integralarticles an amount equal to the width of each article. In the web shown,the forming dies form three articles in each pattern of articles. Thus,the unit makes three normal strokes to advance the three articles in apattern, one at a time. More Specifically, the downward stroke of pusherfingers 166 occurs lwith backward movement of lever 146 to the positionon the small radius portion of cam 142 as shown in FIG. 2. The weight ofcantilever arm 164 causes this downward pushing, to advance the web thewidth of one article. As cam 142 continues to rotate, lever 146 and rod154 are pushed toward the web, to hoist pusher fingers 166. Since thefingers are pivotally mounted on the upper end at 165 to thecantilevered end of arm 164, they move out and around the threedimensional configuration of the next article, to catch behind the nextarticle and push it downwardly in the next stroke. This occurs once witheach revolution of the cam, and thus once with each revolution of thereciprocable trim die 106. After three complete strokes of the trim die,and three shiftings of the web with lever 146 pivoting on its lowermostpivot 150 (FIG. 2), the fourth shift of this lever is of a differentnature.

More specifically, lever 146 is caused on the fourth shift to pivotabout its upper pivot mount 152 because of the contact of an abutment200 (FIG. 4) with the back side of lever 146 opposite cam 142. Thisabutment moves one quarter of a turn on its shaft 202 with eachrevolution of cam 142. Thus, it moves through the four positionsillustrated in FIG. 4, three of which are shown in phantom. Thus, duringthree of the pivotal strokes of lever 146, the lever can pivot about itslower mount 150, without interference from abutment 200. At the fourthstroke, as cam 142 shifts from its small radius portions in contact withfollower 144 to its large radius portions,

the lever cannot shift about pivot 150 because of abuto ment 200. Thisforces it to pivot about upper pivot 152. Consequently, the movement ofthe upper end of the lever, and thus of link 154 attached thereto, isgreater during this fourth stroke because of the leverage occurring withthe closer location of pivot 152 to cam follower 144. This causesfingers 166 to shift the web and articles a greater amount than thenormal stroke, and in fact, an amount preset to equal the `width of onearticle plus the width of space 50d between the two patterns ofarticles. This is preset by vertically adjusting the length of lever 146`with bolts 210 in slots 212 (FIG. 4).

The controlled rotation of abutment 200 (FIG. 4) is achieved by theratchet drive assembly shown in FIGS. 6 and 7. More specifically,mounted on crank shaft 130 is a radially projecting rotating cam 216ywhich rotates one revolution for each revolution of the crank shaft.This cam abuts and shifts a cam follower 218 once each revolution, topivot it on its pivot shafts 220. This pivoting also causes arcuatemovement of radial leg 222 keyed to shaft 220, to thereby hoist theforked end 224 of this shaft once each revolution. This fork end fitsalternately within each of the four notches 226 on rotating ratchetwheel 228 keyed to shaft 202 that mounts the radially projectingabutment 200.

This shaft 202 is mounted rotatably in a pair of spaced bearing journals232 and 234. Thus, each revolution of crank shaft 130 causes pivoting ofarm 222 for shifting ratchet wheel 228 and thus shaft 202 90 to moveabutment 202 through the four positions illustrated in FIG. 4.Consequently, every fourth revolution of the apparatus causes a largeshift of the web and article to cause arm 164, for example, to move tothe second phantom line position at 164 (FIG. 8), rather than the lowerphantom line position.

All of these cam and crank mechanisms on the trim press are driven,therefore, from the belt and pulley assembly 138, 134 and 132. These aredriven by a variable speed drive means 136 shown in FIGS. 2, 9 and l0;This variable speed drive means operates according to a wellknownvariable pulley principle. A first, variable diameter, expandable pulley139 is biased together by coil spring 141. A second, spaced, expandablevariable diameter pulley 149 is mechanically actuated by a hub 143 and alinkage 145 attached thereto and to a threaded rotatable stud 147. Awide drive belt 151 extends around 0 the pulleys. Pulley 149 is drivenby an electrical motor 153. Pulley 139 drives the output shaft 137through speed reduction gears 155.

Variable regulation of the output of the assembly is achieved byrotation of stud 147 to change the size of pulley 149 in housing 240,and thereby force the corresponding change in pulley 139 in housing 239.In this assembly, a hub 244 is afxed to the end of stud 147. A radiallyextending lever 242 is attached to this hub by bolts 243. Lever 242 canshift in the range between an upper stop 246 and a lower stop 248. Thesestops are mounted on a fixed plate 250 which is initially angularlyadjustable with bolt and slot connection 252. On the opposite end oflever 242 from hub 244 is a pivotal connection to the extended cylindershaft 256 of fluid actuated cylinder 258. This fluid actuated cylinderis supplied by pressurized air or fluid through lines 260 and 261 fromsolenoid valve 84 that communicates through a line 262 to a pressurizedsupply (not shown). The solenoid Valve, as stated previously, iscontrolled through electrical leads 7S, 80 and 81 which connect thisunit electrically to web sensor switches 64 and 68 (FIG. l) and to apower supply. This entire assembly controls the speed of operation ofthe trim press in relation to the condition of the web between the twopresses. If the web becomes excessively slack and contacts lower sensorfinger 70 of electrical limit switch sensor 68, the switch is actuatedto complete a circuit through solenoid valve 84, shifting it in onedirection to supply fluid to cylinder 258. The cylinder shifts lever242, which varies the spacing of the pulleys, causing a change of thedrive belt relationship to speed up the drive output to the severalcrank and cam drives for the trim press, with respect to the formingpress. This causes the trim press to operate faster, thereby drawing theslack out of the web.

1f, on the other hand, the web becomes too taut and contacts uppersensor finger 66 of electrical switch 64, this limit switch closes acircuit which shifts solenoid valve 84 in the opposite direction, toretract the cylinder, causing lever 242 to retract and slow down thedrive relationship. Thus, the trim press operates more slowly and causesgreater slack to occur in the web. The unit is thus automaticallycontrolled to maintain a certain range of web slackness between the twopresses.

It is conceivable that this control system could control the formingpress speed rather than the speed of the trim press, but usually it isdesirable to maintain a constant output from the forming press toprevent over heating or under heating of the web prior to forming.

With this apparatus, automatically controlled synchronization alwaysoccurs between the two presses, even though the forming press shifts theweb an amount equal to a pattern of a plurality of articles (herethree), plus the spacing 50c therebetween, and while the trim press onlyshifts the articles one at a time, except for the larger shift toencompass one article and the space therebetween as it moves between twopatterns of articles.

Certain additional advantages may occur to those in the art uponstudying the foregoing disclosure and description. it is alsoconceivable that certain minor variations in structure could be madewithin the concept presented. Hence, the invention is intended to belimited only by the scope of the appended claims and the reasonablyequivalent structures to those defined therein.

We claim:

1. A trim press apparatus for performing -a trim operation on threedimensional articles formed into a generally continuous web in repeatspaced patterns, each of a plurality of articles, comprising:reciprocable trim die means; web advancing means for intermittentlyadvancing successive web portions and articles in said portions intooperative relationship with said die means; said advancing meansincluding a reciprocable pushing pivotal lever means having apredetermined repeat stroke length for advancing the web an amount equalto the width of each article in a pattern; cam means operably associatedwith said lever means, spaced from its pivot, to cause said repeatstroke; and means causing a periodic stroke length greater than saidnormal stroke length for advancing the web an amount equal to the widthof an article plus the spacing between patterns; said last mentionedmeans cornprising a second pivot for said lever means, and intermittentactuating means to cause said cam to pivot said lever means about saidsecond pivot to cause said greater stroke length,

2. A trim press for performing a trim operation on each threedimensional article formed into a generally continuous web in repeatspaced patterns, 'with a plurality of articles in each pattern,comprising: a support frame; reciprocal trim die means on said frame; arotating, power driven y wheel means, crank means operably connectedtherewith and with said die means for reciprocation thereof, and powerdrive means therefor; a rotating can-1 means operably connected to saidpower drive means; reciprocable web advancing pusher means adjacent saiddie means to advance successive articles and surrounding web portions tosaid die means; lever means operably connected to said pusher means,operably engaged by said cam means, and having two spaced pivot mountsat different spacings from said cam means; said lever means normallyshifting about one of said pivot mounts to advance said pusher means apredetermined normal amount equal to the width f an article; leverabutment means adapted to abut said lever between said mounts whenactivated; means operably associated with said advancing means tointermittently activate said abutment means after a repeat number ofpusher strokes, causing said lever means t0 shift about said secondpivot mount, thereby causing said pusher means to shift the web apredetermined diilierent amount over the spacing between articlepatterns in the web.

3. A trim press for performing a trim operation on each threedimensional article formed into -a generally continuous web in repeatspaced patterns, with a plurality of articles in each pattern,comprising: a support frame; reciprocal trim die means on said frame;crank means operably connected with said die means for reciprocationthereof, and power drive means therefor; a rotating cam means operablyconnected to said power drive means; reciprocable web advancing meansadjacent said die means to advance successive articles and surroundingweb portions to said die means; oscillating lever means operably engagedby said cam means, and having two spaced pivot mounts at differentspacings from said cam means; oscillatory link means connecting saidlever means and said advancing means; said lever means normally shiftingabout one of said pivot mounts to shift said link means and advancingmeans a predetermined normal amount; lever abutment means adapted toabut said lever between, said mounts when activated; shifting means forsaid abutment means; means operably associating said shifting means withsaid cam means to intermittently activate said abutment means after arepeat number of strokes of said advancing means, causing said levermeans to shift about said second pivot mount, thereby causing saidpusher means to shift the web a predetermined different amount over thespacing between article patterns in the web.

References Cited UNITED STATES PATENTS 938,876 11/1909 Krummel 226-1233,228,066 1/1966 Rippstein l819 JAMES M. MEISTER, Primary Examiner.

